Ring-structure and the vortex

[Images: The structural science of vortex rings. “A vortex ring forms when a very quick burst of fluid shoots out of an opening,” Freud writes – er, this article tells us. “As the fluid moves forwards, it spreads out and its front edges curl back. If the speed of the burst is fast enough, the curling fluid eventually curls all the way round, until it is travelling forwards again in the direction of the original burst.” Etc. So could such vortices be used as a new form of undersea propulsion – or perhaps an underwater art show, perfect vortices spiraling off through colored water, liquid crystals, magma? If you’re still curious, this PDF version of the New Scientist article mentioned above will tell you all about the fluid-mechanical work of Kamran Mohseni and Mory Gharib, including a brief aside on “superfluid gyros” and “vortex-formation velocity.”]